1. Field of the Invention
The present invention relates to a tube joint for a fluid. In particular, the present invention relates to a tube joint which is provided with an attachment/detachment mechanism for a socket and a plug.
2. Description of the Related Art
When a fluid supply source and a fluid consumption source are piped to one another by using, for example, a hose or a hard pipe or tube, a variety of tube joints, each of which is composed of a socket and a plug for facilitating connection and separation, have been hitherto used.
In relation to the tube joint of this type, for example, the following structure is disclosed in Japanese Laid-Open Utility Model Publication No. 51-69119. A cutout is provided on the outer circumference of a slide sleeve for fitting/detaching a one-touch coupling. A pin, which is engageable with the cutout, is secured to the outer surface of the socket. The slide sleeve is released from the locked state only when the position of the pin is coincident with the position of the cutout in the axial direction. The socket and the plug can be detached from each other by slidably moving the slide sleeve in the axial direction.
In other words, the tube joint, which is disclosed in Japanese Laid-Open Utility Model Publication No. 51-69119, is constructed as follows. That is, the locked state is established, in which the slide sleeve cannot be slidably moved in the axial direction when the position of the pin is not coincident with the position of the cutout in the axial direction by rotating the slide sleeve in the circumferential direction in the state in which the socket and the plug are connected to one another.
However, in the case of the tube joint disclosed in Japanese Laid-Open Utility Model Publication No. 51-69119 described above, the positional relationship is unstable between the slide sleeve and the pin in the locked state. It is feared that the slide sleeve may be rotated in the circumferential direction by applying any unexpected external force to the slide sleeve to provide the unlocked position at which the position of the pin is coincident with the position of the cutout, and the socket and the plug may be separated from each other.